1. Field
Example embodiments discussed herein are directed to image processing of image data. The example embodiments may relate to noise removal processing for the image data.
2. Description of the Related Art
Japanese Patent Laid-Open Publication No. 1988-91783 discloses a smoothing technique for removing noise in image data so as to clearly display a boundary surface of the image. Japanese Patent Laid-Open Publication No. 2006-279709 discloses an information processing apparatus for removing the noise in the image data with a smoothing operation.
In some cases, a plurality of pixels forming an image picked up by an image pickup element includes continuous noise pixels. The following are typical examples of the above-described continuous noise pixels. The plurality of noise pixels are pixels in a line in a vertical scanning direction or form a block of continuous noise pixels in both lateral and longitudinal directions, for example. Continuous noise pixels affect an image resulting from reproduction. For example, the continuous noise pixels generally have a detrimental affect on image quality. However, it has been difficult to remove the continuous noise pixels with the conventional smoothing operations.
The continuous noise pixels are caused when defective pixels are found in the image pickup element or when the images are picked up with high-sensitivity. The noise due to such defective pixels, or due to an image pickup operation with high-sensitivity, is impulsive noise. The rate of occurrence of the impulsive noise does not follow Gaussian distribution, and the amplitude of the impulsive noise is irregular. Impulsive noise affects the output image. However, it has been difficult to sufficiently remove such impulsive noise with the conventional smoothing operations.